Katy is an Associate Professor of Physical Geography at the University of Exeter. An experienced sea-going oceanographer, her research explores the physics of our oceans and atmosphere. She has pioneered acoustic methods to capture ocean flows deep below the surface layers – flows that span tens of kms to microscale mixing. Such methods will help to better understand how the oceans harness energy from the winds and tides to distribute properties such as the heat, carbon and nutrients across the globe. Her expertise also spans Southern Ocean dynamics and turbulent mixing, mapping marine plastic transport, ocean-atmosphere carbon exchange, and rainfall variability in sub-saharan Africa. Through her work, she is passionate about improving our understanding of climate variability and the health of the marine environement. Katy is part of the Centre for Geography and Environemental Science which sits in the Department of Earth and Environmental Science, and the Exeter Marine network

Interests:

Subsurface Ocean Flows: from eddies to turbulence

One of the key uncertainties in our climate system today is the future storage capacity of heat and carbon in the ocean, alongside the distribution of nutrients and oxygen, key ingredients for a healthy marine ecosystem. To address these uncertainties, improved knowledge of how the oceans move deep below the surface layers is required. In particular, a better understanding of interior ocean flows that span tens of metres to tens of kilometers (i.e. submesoscales) is critical: submesoscale flows provide a pathway to harness energy from the winds and tides and use it to stir and mix different water masses around the globe, along with the heat, carbon and nutrients that they carry. However, the intermediate size and intermittent nature of subsurface submesoscale flows make them both difficult to resolve with observations or model with computers. We are interested in addressing this challenge through the field of Seismic Oceanography. Seismic oceanography utilises acoustic reflections, as collected by the hydrocarbon industry, to image temperature and salinity changes within the water column. Similar to how bats echo-locate, a ship at the surface releases sound pulses into the water and records reflections from water layers. Seismics oceanography is unique in its ability to map out large swathes of ocean structure at unprecedented horizontal resolutions (two orders of magnitude better than other techniques), providing information about subsurface flows from mesoscale eddies (100 km) through to turbulence and mixing.

Southern Ocean Dynamics and Carbon Uptake

The Antarctic Circumpolar Current (ACC) that encircles the Antarctic continent, plays a leading role in regulating the Earth’s climate system. Eddies, internal waves and small scale mixing processes are an important component of ACC circulation and dynamics. Better quantifying the rates and geographical distribution of the small-scale turbulent mixing in the Southern Ocean, will ultimately help to understand how the global oceans transport of heat, carbon and other important climate variables.

During my post-doc which was part of the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) project, we made some of the first dedicated measurements of abyssal turbulent mixing and variability in the Southern Ocean, and how they relate to the larger scale flow. This work has provided unprecedented insights into the mechanisms by which the deep waters of the global oceans are ultimately driven back to the surface, where they can interact with the atmosphere.

Here is a link to a film which we made during a field campaign to the Southern Ocean and Antarctica: A Drop in the Southern Ocean - Fereday Films

Sahel Summer Rainfall Variability

The Sahel region of Africa is particularly vulnerable to climate variability. Exhibiting some of the largest rainfall changes worldwide and with a community reliant on agricultural productivity, droughts are major natural disasters for the region. Given that our Earth’s climate is in a state of rapid change, accurate forecasting and a better understanding of the Sahel summer rainy season is of fundamental importance for implementing successful adaptation strategies to ensure the future food security and economic wealth of sub-Saharan Africa.

Working with the inter-annual and decadal climate prediction team at the Met Office, we have utilized state of the art climate models to show that both inter-annual rainfall fluctuations and prolonged drought periods can be successfully predicted across the Sahel. Key to our confidence in the observed statistical skill is the ability to also predict the dominant physical processes that modulate Sahel rainfall. This work has shed new light on the character of Sahel rainfall change on different timescales, particularly in relation to how the different ocean basins impact both the moisture advected into the Sahel and the dynamics that promote ascent of locally sourced moisture. Here is a short film about the work and a visit to Senegal and Ghana to build research collaborations and talk with schools.

Career:

Katy completed her undergraduate in physics at the University of Cambridge where she continued to study for a PhD in geophysics/seismic oceanography. Before taking up her lectureship at Exeter, she worked as a researcher at the University of Southampton and the Met Office Hadley Centre for Climate Science and Services. Katy currently holds a prestigious UKRI Future Leaders Fellowship and is Principal Investigator on a NERC Exploring the Frontiers grant. To date, she has raised over £4.3 million of grant income.

Committed to wider ocean stewardship, Katy is the UK delegate for International Association for the Physical Sciences of the Oceans and committee member of the International Union of Geodesy and Geophysics. She sits on the University NERC Funder Advisory Network (FAN). Katy has a passion for sharing her knowledge and nurturing and inspiring future ocean scientists. She leads an active team of PhD students and post-doctoral researchers and has supervised several MSc and undergraduate dissertations. She is Programme Director for Exeter’s BSc Marine Science degree, college Widening Participation Office, an experienced Academic Tutor and has led and developed several undergraduate courses. Katy has given many public engagement talks and had her research showcased in the international media and press (iNews, Science Daily & radio interviews).

Postgraduate researchers
Isabelle Cox - PhD student investigating low-oxygen zone biogeochemistry
Laura Byrne - PhD student in modelling Antarctic ice sheet evolution
Wuyi Zhao - PhD looking at the impact of eddies on ocean biogeochemistry
Yao Meng - PhD student in seismic oceanography (Mozambique Channel)

Marika Takeuchi - Post Graduate Research Fellow investigating using acoustics to map marine snow

Tobias Ehman - Post Graduate Research Fellow on COSSMoSS, using acoustics to map submesoscale currents

Alumni
Daniel Ford - PhD student in ocean-atmosphere carbon fluxes
John Bruun - Research Fellow investigating the role of sea surface temperatures and variability in sub-Saharan rainfall
Tobias Ehmen - PhD student in seismic oceanography (Southern Ocean)

Tobias Ehmen - Post Graduate Research Fellow investigating using acoustics to map marine snow

Andrea Rochner - PhD student in modelling carbon uptake in the Southern Ocean

Daniel Wilson - PhD student in modelling microplastic pathways in the Southern Ocean